Sudoku in its modern form was invented by Howard Garns, an American architect, and first published as "Number Place" in Dell Pencil Puzzles and Word Games in May 1979. The Japanese publisher Nikoli brought it to Japan in 1984 under the name "Sūji wa dokushin ni kagiru", and the name was shortened to Sudoku. It became a worldwide craze after The Times of London began printing it on 12 November 2004. The dates and names below come from the named sources at the end of each section.
Howard Garns (1905 to 1989), a retired architect from Connersville, Indiana, designed the puzzle that we now call Sudoku. It appeared as "Number Place" in Dell Pencil Puzzles and Word Games in May 1979, on a 9x9 grid with nine 3x3 boxes and the rule that 1 to 9 appear once in every row, column and box.
Dell printed no byline. Puzzle editor Will Shortz worked out the authorship in 2005: Garns's name was listed among the contributors only in the issues that contained Number Place. Garns died in 1989 and never saw the craze.
Garns built on older ideas. Leonhard Euler studied Latin squares in the 18th century, grids where each symbol appears once in every row and column, with no boxes and no solving. In France, the newspaper Le Siècle printed a 9x9 magic square with 3x3 sub-squares on 19 November 1892, and La France refined it in 1895. Neither was the puzzle we play today, because neither combined the row, column and box rule in one solving puzzle. (Sources: Wikipedia articles "Sudoku" and "Howard Garns", which cite Will Shortz's 2005 identification of Garns.)
Sudoku is short for the Japanese phrase "Sūji wa dokushin ni kagiru", which means "the digits must be single". The full phrase became the puzzle's Japanese title when Nikoli's president, Maki Kaji, introduced it in April 1984. He then shortened it by taking the first kanji of each compound word: sū (数, number) and doku (独, single or alone), giving 数独, Sudoku. The name describes the rule: each digit occurs once in its row, column and box.
Nikoli also set its own standards for puzzles: clue cells placed symmetrically and a single solution per puzzle. The mathematics of Sudoku explains why a unique solution needs a minimum number of clues. (Sources: Wikipedia "Sudoku"; Nikoli's history as reported there.)
| Year | Event |
|---|---|
| 1780s | Leonhard Euler studies Latin squares |
| 1892 | Le Siècle prints a 9x9 magic square with 3x3 sub-squares |
| May 1979 | Howard Garns's "Number Place" appears in Dell Pencil Puzzles and Word Games |
| April 1984 | Nikoli publishes it in Japan as "Sūji wa dokushin ni kagiru", later Sudoku |
| 1997 | Wayne Gould finds a Sudoku book in a Tokyo bookshop |
| 12 November 2004 | The Times of London starts publishing Sudoku |
| 2005 | Will Shortz identifies Garns as the inventor |
| 2006 | First World Sudoku Championship |
Wayne Gould, a New Zealander and recently retired Hong Kong judge, found a Sudoku book in a Tokyo bookshop in 1997. He spent about six years writing software that could generate puzzles, then persuaded The Times of London to print them. The first Times puzzle ran on 12 November 2004, and other British and international papers followed within months. (Source: Wikipedia "Sudoku".)
Sudoku now lives in newspapers, books, apps and websites, and competitive solving has grown into an organised sport with the World Sudoku Championship, first held in 2006. Puzzle designers keep inventing variants that change the rules of the grid, such as killer cages or larger boards. To start playing, read how to play Sudoku and pick an Easy puzzle on the home page. Curious about the other extreme? See the hardest Sudoku puzzles, or ask whether Sudoku is good for your brain.